Where does “tap-” come from?

tap- (Proto-Indo-Aryan) comes from Proto-Indo-Iranian tap-, from Proto-Indo-European tep- — to be warm, be hot.

Ancestry of “tap-”, step by step

StepLanguageWordMeaning
1Proto-Indo-Iraniantap-—
2Proto-Indo-Europeantep-to be warm, be hot
Every word from Proto-Indo-European tep- →Every word from Proto-Indo-Iranian tap- →